The Philippines bishops' conference has warned President Benigno Aquino against changing the constitution to allow him to run for another term in office.

"I cannot lend support to constitutional amendments that merely serve the purposes of one office holder or one class of persons," said Archbishop Socrates Villegas of Lingayen-Dagupan, president of the bishops' conference.

Villegas said constitutional amendments are justified only in the measure that they "redound to the benefit of the nation and address long-festering problems arising out of ambiguities in the constitution".

On Wednesday, Aquino said he is open to amending the country's constitution to allow him to run for another six-year term. The president said he would listen to the "voice of the people" if they want him to continue the "reforms" he started.

On Friday, a number of small protests sprouted up around the Philippine capital Manila against the possibility of Aquino extending his term, which expires in 2016.

"We have ousted a dictator before, we'll kick out a wannabe dictator today," said Vencer Crisostomo, chairman of the youth group Anakbayan.

Crisostomo said nationwide protests will be held August 25 to show that people are "sick and tired of the systemic corruption in our society".

The Philippine Council of Evangelical Churches on Friday also joined calls for Aquino not to extend his term of office.

"It is best for him to just endorse a new leader who would faithfully continue his fight against corruption," said Bishop Efraim Tendero, council national director.

"I'm praying and hoping that President Aquino would finish well as a good leader, and what he started in the struggle for a 'righteous path' will be passed smoothly to his successor."

The council cautioned Aquino not to be corrupted by the "misleading voices" of people around him.